the dart-define argument is not working for build

I am using

flutter build apk --obfuscate --split-debug-info=./build/info-apk --split-per-abi --dart-define=SOME_VAR=true

and

final someVar = String.fromEnvironment('SOME_VAR', defaultValue: 'false').toLowerCase() == 'true'

but someVar is false in the apk, what is wrong?

My flutter version: 2.2.3